几种地形校正方法的研究

A Study of Some Terrain Reduction Methods

本文推证了三种典型的地形校正方法(局部地形改正(C),剩余地形改正(RTM)爱黎-海斯卡宁型地形均衡改正(t_C)之间的数学关系,对其特性进行了分析比较;讨论了它们实现的途径(数据处理方法)及其计算特征;最后还应用某地区的实测地形高数据进行了实际计算,得出了一些有益的结论。

The paper has evaluated the relationships among three terrain reduction procedures(terrain correction, isostatic reduction, residual terrain reduction (RTM) and given themethods of their data processing. The emphasis has been laid to speed the computationand deal with the singular integration properly. Our major conclusions are as follows: —— To the near zone of the computated point, or the ′innermost zone′, the te-rrain heights have a critical effect on the terrain reduction results, and the discrete int- egration need to be done particularly. The (terrain) height data in the innermost zonemust be densified to decrease discrete error, the best method is bicubic spline function. —— It is necessary to obtain detailed terrain height data in the innermost zone.(generally speaking, within 10～50km radius is enough). —— It is highly important to consider the speed of computation. If there are manyterain reduction points to be computated and the points are regular arranged, FFTalgorithm is effective to save computer time.